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Toner and developing device using the same

a technology of developing devices and toners, applied in the field of toners, can solve the problems of reducing the transfer efficiency and filming on the photoconductor surfa

Inactive Publication Date: 2005-09-29
SEIKO EPSON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0026] In the present invention, a toner contains a toner mother particle, an amorphous fine particle, a monodisperse spherical silica and a metal soap, and in this toner, the amorphous particle has the same polarity as the toner mother particle, a volume mean particle size of 0.1 times or less that of the toner mother particle, and a work function larger than that of a cleaning blade or a roll brush of a developing device, and an average sphericity of the toner mother particle expressed by L0 / L1 is from 0.970 to 0.985, provided that L1 represents a circumferential length (μm) of a projected image of the particle, and L0 represents a circumferential length (μm) of a true circle having an area equal to that of the projected image of the particle. Thereby, the amorphous fine particle can be prevented from leaving the surface of the toner mother particle and even if liberated from the surface of the toner mother particle during continuous image formation, the particle liberated can hardly attach to the non-image area on the latent image carrier because it has the same polarity as the toner mother particle. Furthermore, since the particle is negatively charged, this particle can be transferred onto the intermediate transfer medium from the photoconductor in the primary-transfer part and cleaned by a cleaning blade or a roll brush mounted to the intermediate transfer medium.

Problems solved by technology

However, when image formation is continuously performed under the condition of thin layer regulation by using a toner having an excellent transfer efficiency and disengaging the cleaning device from the latent image carrier, the external additive with a large particle size is gradually liberated from the toner surface and since the charged polarity is opposite the polarity of the toner mother particle, this external additive electrostatically adheres to the non-image area of the photoconductor and causes filming on the photoconductor surface.
This gives rise to fogging or reversal transfer toner and at the same time, disadvantageously leads to reduction in the transfer efficiency.

Method used

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  • Toner and developing device using the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

Production of Toner by Polymerization Method

Production of Toner Mother Particle 1

[0128] A monomer mixture comprising 80 parts by weight of styrene monomer, 20 parts by weight of butyl acrylate and 5 parts by weight of acrylic acid was added to an aqueous solution mixture containing 105 parts by weight of water, 1 part by weight of nonionic emulsifier (Emulgen 950, produced by Dai-ichi Kogyo Seiyaku Co., Ltd.), 1.5 parts by weight of anionic emulsifier (Neogen R, produced by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 0.55 parts by weight of potassium persulfate, and polymerized at 70° C. for 8 hours with stirring in a nitrogen stream. By cooling after polymerization reaction, a milky white resin emulsion having a particle size of 0.25 μm was obtained.

[0129] Thereafter, 200 parts by weight of the resin emulsion obtained above, 20 parts by weight of polyethylene wax emulsion (Permarin PN, produced by Sanyo Chemical Industries, Ltd.) and 7 parts by weight of phthalocyanine blue were dispe...

production example 1

of Toner

[0175] First, 0.8 parts by weight of hydrophobic silica having a mean primary particle size of 12 nm, which is a fluidity improving agent, and 0.7 parts by weight of hydrophobic silica having a mean primary particle size of 40 nm were added and mixed per 100 parts by weight of Toner Mother Particle 1 to prepare a toner.

[0176] Thereafter, toners containing 0.4 parts by weight of monodisperse spherical silica having a mean particle size distribution shown in Table 2, 0.5 parts by weight of hydrophobic titanium oxide of 20 nm, 0.2 parts by weight of hydrophobic titanium oxide having a particle size distribution of 200 to 750 nm in terms of the primary particle size and being treated with a negatively chargeable n-butyltrimethoxysilane coupling agent and further with zinc stearate, and 0.2 parts by weight of metal soap (fine particulate calcium stearate (M7StCa), produced by NOF Corporation) shown in Table 4 were produced and designated as Toner 1-1, Toner 1-2 and Toner 1-3, re...

example 2

[0190] Toners containing 0.7 parts by weight of hydrophobic silica having a mean primary particle size of 7 nm, which is a fluidity improving agent, 0.6 parts by weight of hydrophobic silica having a mean primary particle size of 40 nm, 0.4 parts by weight of hydrophobic titanium oxide having a mean primary particle size of 20 nm, 0.4 parts by weight of Monodisperse Spherical Silica 2 shown in Table 2, which was hydrophobed with a hexamethyldisilazane coupling agent, 0.2 parts by weight of hydrophobic titanium oxide having a particle size distribution of 200 to 750 nm in terms of the primary particle size and being treated with a negatively chargeable n-butyltrimethoxysilane coupling agent and further with zinc stearate, and 0.2 parts by weight of metal soap shown in Table 5, per 100 parts by weight of Toner Mother Particle 2 (mean particle size on the volume basis: 7.9 μm, mean particle size on the number basis: 7.0 μm, work function: 5.64 eV, sphericity: 0.976) of Example 1 were p...

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PUM

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Abstract

The present invention provides a toner including: a toner mother particle; an amorphous fine particle; a monodisperse spherical silica; and a metal soap, wherein the amorphous particle has the same polarity as the toner mother particle, a volume mean particle size of 0.1 times or less that of the toner mother particle, and a work function larger than that of a cleaning blade of a developing device, wherein an average sphericity of the toner L0 / L1 is from 0.970 to 0.985, provided that L1 represents a circumferential length (μm) of a projected image of the toner particle, and L0 represents a circumferential length (μm) of a true circle having an area equal to that of the projected image of the toner particle.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a toner for an image forming apparatus of forming an image by developing a latent image formed on a latent image carrier. More specifically, the present invention relates to a toner suitable for an image forming apparatus where toner images are successively formed on an image carrier by using toners of multiple colors and after transferring these images on an intermediate transfer medium by applying a transfer voltage, the image is transferred on a recording material such as paper. The present invention also relates to a developing method using the toner. BACKGROUND OF THE INVENTION [0002] In a background art, in same image forming apparatus, an apparatus has a latent image carrier comprising a photoconductor drum or a photoconductor belt, where at the image forming operation, an electrostatic latent image is formed on a photosensitive layer of the photoconductor, the latent image is then developed with a developer of a ...

Claims

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Application Information

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IPC IPC(8): G03G9/08G03G9/087G03G9/097G03G15/08
CPCG03G9/0827G03G9/09791G03G9/09725G03G9/09708
Inventor MIYAKAWA, NOBUHIROIKUMA, KEN
Owner SEIKO EPSON CORP